What is the Google dance?
When a search is made on Google, it is processed by of one of the data centers. Google has installed some all over the world, in order to be able to respond as quickly as possible on a global scale.
They choose the datacenter which will deliver the page results depending on various parameters ranging from the geographical situation of the user to the traffic load handled by each center.
A few years ago, there were plenty of major differences between the many data stored on these various servers.
Furthermore, a popularity indicator calculated by Google called PageRank was not calculated in real time. It was therefore necessary to wait for Google to publicly share these new values.
The Google Dance was then the time period when all Google data centers aligned their data and when the value of PageRank was updated.
SEO professionals impatiently awaited the Google Dance in order to concretely observe the results of part of their work. Most of the time, this dance took place on the eve of full moon nights.